(1) Field of the Invention
The present invention relates to an improved automatic pellet carrier fed pellet implanting apparatus particularly adapted for implanting medicament pellets in animals and the like. In particular, the present invention relates to an automatic gun apparatus for implanting medicament pellets which uses a pellet carrier for advancing pellets into an opening in the carrier. The carrier is preferably mounted in a side opening of a linearly moveable head assembly which is mounted in a nose section of the gun apparatus. A receiving slot is provided in a side wall of the nose section so that when the gun apparatus is actuated to implant a pellet, the carrier and the head assembly move in the gun apparatus, along a longitudinal axis with the carrier moving in the receiving slot towards the rear of the gun and away from the animal. The head assembly also mounts a hypodermic needle having a barrel for injecting the pellet into the animal. At the same time that the head assembly, the carrier and the needle move away from the animal, a pellet is advanced into the animal by a drive rod traveling along the longitudinal axis and through a bore in the head assembly, the opening in the carrier and through the barrel of the needle, with the pellet being deposited in the animal unobstructed by the needle. Releasing the trigger causes a first return spring means to return the head assembly, the needle and the carrier to the front of the gun apparatus while a second return spring retracts the drive rod along the axis to the back of the gun apparatus. Once the drive rod has left the bore in the head assembly, the pellets in the carrier are advanced along a second, perpendicular axis by a spring actuated plate in the carrier, to register the next pellet in the carrier in the opening through the carrier along the longitudinal axis.
(2) Prior Art
The prior art has described various types of hand held pellet implanting gun apparatus. These gun apparatus use essentially two types of carriers for medicament pellets for implanting in animals and the like. The first type uses a rigid rectangular cross-sectioned pellet carrier that is mounted at the front of the gun apparatus adjacent to a hypodermic needle. A trigger actuated drive rod in the gun apparatus travels through an indexed pellet chamber along a longitudinal axis and moves a pellet into the needle for implanting. After the pellet has been implanted and the trigger has been released, a mechanical mechanism advances the carrier along a second axis that is perpendicular to the longitudinal axis for registering the next pellet chamber in the carrier along the longitudinal axis. The rectangular carrier type of gun apparatus has numerous mechanical components and requires considerable precision in order for the gun apparatus to function. Illustrative of the rectangular pellet carriers are U.S. Pat. No. 4,004,565 to Fischer et al; U.S. Pat. No. 4,077,406 to Sandhage et al; U.S. Pat. No. 4,403,610 to Lodge et al; U.S. Pat. No. 4,447,223 to Kaye et al; and U.S. Pat. No. 4,687,465 to Prindle et al. British Patent No. 1,583,816 to Turley is also illustrative of the rectangular type of pellet carriers.
The second type of gun apparatus uses a cylindrical carrier that is mounted in a housing at the front of the gun apparatus. In the cylindrical type carriers, after a trigger actuated drive rod travels through an indexed pellet chamber and moves a pellet along a longitudinal axis and into a hypodermic needle for implanting, a mechanical mechanism rotates the carrier in a plane perpendicular to the longitudinal axis to register the next pellet chamber along the axis. The cylindrical carriers are similar to the rectangular carriers in that neither type of carrier travels linearly along the longitudinal axis when the trigger is actuated to implant a pellet into an animal and the like. The cylindrical carrier type of gun apparatus has numerous mechanical components and requires considerable precision in order for the gun apparatus to function. Illustrative of the cylindrical carriers are U.S. Pat. Nos. 3,669,104 to Wyatt et al; 3,774,607 to Schmitz; 4,531,938 to Kaye et al; and 4,576,591 to Kaye et al.